Bioprocess Engineering 2nd Edition by Fikret Kargi,Michael Shuler

Exercise 11

5 The bioconversion of glucose to ethanol is carried out in a packed-bed, immobilized-cell
bioreactor containing yeast cells entrapped in Ca-alginate beads. The rate-limiting substrate
is glucose, and its concentration in the feed bulk liquid phase is
The nutrient flow
rate is F = 2 l/min. The particle size of Ca-alginate beads is
= 0.5 cm. The rate constants
for this conversion are

for the following rate expression:

The surface area of the alginate beads per unit volume of the reactor is
and
the cross-sectional area of the bed is
Assuming a first-order reaction-kinetics
(e.g., relatively low substrate concentrations), determine the required bed height for 80% con-
version of glucose to ethanol at the exit stream. Hint: To calculate the effectiveness factor, we
can use the following equations: